This is a randomized, double-blind, placebo-controlled, parallel group, multicenter study. This study will consist of a Screening Period, followed by a Single-Blind Placebo Run-in period. The Double-blind Treatment period (14±2 days) will begin at randomization/Day 1 and consist of an interim visit 7±1 days after randomization, and an End of Study (EOS)/Early Termination (ET) visit. All subjects will have either a telephone contact, or in some cases an in-clinic visit, 7±2 days after their last study visit. This study was previously posted by Sepracor Inc. In October 2009, Sepracor Inc. was acquired by Dainippon Sumitomo Pharma., and in October 2010, Sepracor Inc's name was changed to Sunovion Pharmaceuticals Inc.